The present invention relates to a cooking utensil such as a microwave oven, an electric heating oven, a gas oven and a combination thereof.
The present invention relates, more particularly, to a cooking utensil including a plurality of sensors for detecting a cooking condition of foodstuff disposed in the cooking utensil, and an automatic selection feature of the plurality of sensors in response to manual selection of a cooking menu.
A microwave oven has been developed which includes a thermistor for controlling the microwave generation in response to an output signal derived from the thermistor. The thermistor is disposed in an exhaustion duct for detecting an exhaustion air temperature developed from an oven cavity, whereby the microwave generation is terminated when the exhaustion air temperature reaches a preselected value.
Another microwave oven is proposed in my copending application Ser. No. 71,179, "COOKING UTENSIL CONTROLLED BY GAS SENSOR OUTPUT," filed On Aug. 31, 1979, wherein a gas sensor is disposed in an exhaustion duct for detecting a gas concentration developed from an oven cavity. When the gas concentration reaches a preselected value, the gas sensor output shows a preselected value, and in response thereto the microwave generation is terminated.
The thermistor controlled microwave oven is effective when the exhaustion air temperature is higher than 70.degree. C. at the end of the cooking operation. The gas sensor controlled microwave oven is effective for performing the grill operation, for example, for detecting a completion of the broiling of fish. The gas sensor controlled microwave oven is, in addition, suited for warming "sake," wherein the exhaustion air temperature is around 40.degree. C. through 50.degree. C. at a preferred completion of the warming.
Accordingly, an object of the present invention is to provide a cooking utensil responding to output signals derived from a plurality of sensors disposed in the cooking utensil.
Another object of the present invention is to provide an automatic selection circuit for automatically enabling an output signal derived from a preferred sensor in response to manual selection of a cooking menu.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description gives hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, a temperature sensing thermistor and a gas sensor are disposed in an exhaustion duct of a microwave oven. A menu selection manual lever is provided on a control panel for selecting a cooking menu among, for example, warming milk, rewarming foodstuff, defrosting and warming SHAO-MAI, warming hamburg steak, warming SAKE, broiling fish, boiling vegetables, and grilling meat. When a desired menu is selected through the menu selection manual lever, the microwave generation operation is conducted till the sensor output shows a preselected value correlated to the respective menu.
A control circuit is provided for automatically selecting the thermistor or the gas sensor in response to the manual selection of the menu. More specifically, when one of the above-mentioned first four menus is manually selected, the control circuit functions to utilize the thermistor output for detecting the completion of the cooking operation. When one of the above-mentioned last four menus is manually selected, the control circuit functions to utilize the gas sensor output for detecting the completion of the cooking operation.